45.1 hormones and signaling molecules Flashcards
hormone
molecule secreted into extracellular fluid to send messages throughout body
nervous system
neurons transmit signals everywhere
endocrine glands vs
exocrine gands
endo=secrete hormones into surrounding fluid
exo=secrete substances onto body surfaces and body cavities
local regulators
secreted molecules that act short distance
-reach target only by diffusion
paracrine
target is near cell
autocrine
secreted molecules act on secreting cell itself
neurotransmitters
chemicals that diffuse short distances to target cell receptors
neuroendocrine signaling
neurosecretory cells (brain) secrete molecules that diffuse from nerve cell endings into bloodstream to reach target cells
- -neurohormones
ex. ADH for kidneys for water balance
pheromones
chemicals released into the external environment